View Single Post
Old 04-17-2009, 12:20 PM   #960 (permalink)
MPaulHolmes
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,832

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,362
Thanked 1,202 Times in 765 Posts
Quote:
Originally Posted by MazdaMatt View Post
Current feedback pwm control using PI is really not that hard to implement or processor intensive... we're just using a really bottom-of-the-barrel processor. It also makes hardware limited completely moot except in disaster fail cases.
Hey! I'm upgrading the speed to 16.000 MHZ! Wow! I don't want to complain about this processor, but it would be sort of nice to have floating point for the PI loop rather than fixed point math. I only have 16 bit numbers available (simulated in software! Actually it's all 8 bit!), which makes the decimal resolution with fixed point math pretty small, so as to avoid overflow. We're talking +- 1/64 or maybe +- 1/128. Maybe that's OK, but I had a really hard time finding the right P and I with all the noise in the system last time!

It might be much better this time, because a lot of the noise issues are being eliminated! ya!
__________________
kits and boards
  Reply With Quote